A shock tube study of the reaction S + H2 ⇌ SH + H in pyrolysis and photolysis systems

Atomic resonance absorption spectroscopy (ARAS) was applied to measure S atoms, behind shock waves in COS/H₂ pyrolysis or CS₂/H₂ photolysis systems. Both the pyrolysis of COS and the photolysis CS₂ was used to generate the S atoms, which subsequently reacts with H₂ via the reaction: The photolysis experiments were designed to provide clear first-order conditions for reaction (R3); i.e., the H₂ concentration exceeds that of S by at least a factor of 100. The S atom profiles obtained during pyrolysis of highly diluted COS/H₂/Ar mixtures were analyzed by computer simulations based on a simplified reaction mechanism using the rate coefficient k₃ as a fitting parameter. Both groups of experiments covered the temperature range of 1257 K ? T ? 3137 K and lead to a rate coefficient of: . © 1995 John Wiley & Sons, Inc.